


Detailed explanation of how php uses regular expressions to obtain the URL in a string
The client passes a string and all URLs need to be matched from the string. How to achieve this in PHP? This article introduces how PHP obtains the URL (website link) in a string. It mainly uses the PHP regular expression function preg_match_all. Please see below for the specific implementation method
$str ='本文实例讲述了php匹配字符串里所有URL地址的方法。http://www.manongjc.com 分享给大家供大家参考'; preg_match_all("/http:[\/]{2}[a-z]+[.]{1}[a-z\d\-]+[.]{1}[a-z\d]*[\/]*[A-Za-z\d]*[\/]*[A-Za-z\d]*/",$str,$array2); print_r($array2);
The running result is:
( [0] => Array ( [0] => http://www.manongjc.com ) )
The preg_match_all function is mainly used here. The specific usage of this function is as follows:
preg_match_all — Perform global regular expression matching
Syntax:
int preg_match_all ( string pattern, string subject, array matches [, int flags] )
Search in subject for all patterns given by pattern Regular expression matches content and puts the results into matches in the order specified by flags.
After searching for the first match, subsequent searches start from the end of the previous match.
Pay special attention to PREG_PATTERN_ORDER and PREG_SET_ORDER
flags can be a combination of the following flags (note that it makes no sense to use PREG_PATTERN_ORDER and PREG_SET_ORDER together):
If you use PREG_PATTERN_ORDER
Sort the results so that $matches[0] is an array of all pattern matches, $matches[1] is an array of strings matched by the subpattern in the first bracket, and so on. (That is, $matches[0] [0] is the second item in all pattern matches, $matches[0] [1] is the second item in all pattern matches, $matches[1] [0] is the match for each item. The first item in brackets, $matches[1] [0] matches the second item in each bracket)
##
<?php preg_match_all ("|<[^>]+>(.*)</[^>]+>|U","<b>example: </b><p align=left>this is a test</p>",$out, PREG_PATTERN_ORDER); /* http://www.manongjc.com/article/1591.html */ print $out[0][0].", ".$out[0][1]."\n"; print $out[1][0].", ".$out[1][1]."\n"; ?>
<b>example: </b>, <p align=left>this is a test</p> example: , this is a test
##The above is this article The entire content, I hope it will be helpful to everyone's study.
Related recommendations:
Regular expressionExamples of matching, replacement and segmentation functions
Regular expressionExample analysis of matching replacement and segmentation functions
Regular expressionStatement Detailed explanation of the comment steps
#regular expressions most commonly used in PHP
The above is the detailed content of Detailed explanation of how php uses regular expressions to obtain the URL in a string. For more information, please follow other related articles on the PHP Chinese website!

Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

Notepad++7.3.1
Easy-to-use and free code editor

SublimeText3 Chinese version
Chinese version, very easy to use

Zend Studio 13.0.1
Powerful PHP integrated development environment

Dreamweaver CS6
Visual web development tools

SublimeText3 Mac version
God-level code editing software (SublimeText3)

Hot Topics

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

If you are an experienced PHP developer, you might have the feeling that you’ve been there and done that already.You have developed a significant number of applications, debugged millions of lines of code, and tweaked a bunch of scripts to achieve op

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

JWT is an open standard based on JSON, used to securely transmit information between parties, mainly for identity authentication and information exchange. 1. JWT consists of three parts: Header, Payload and Signature. 2. The working principle of JWT includes three steps: generating JWT, verifying JWT and parsing Payload. 3. When using JWT for authentication in PHP, JWT can be generated and verified, and user role and permission information can be included in advanced usage. 4. Common errors include signature verification failure, token expiration, and payload oversized. Debugging skills include using debugging tools and logging. 5. Performance optimization and best practices include using appropriate signature algorithms, setting validity periods reasonably,

This tutorial demonstrates how to efficiently process XML documents using PHP. XML (eXtensible Markup Language) is a versatile text-based markup language designed for both human readability and machine parsing. It's commonly used for data storage an

A string is a sequence of characters, including letters, numbers, and symbols. This tutorial will learn how to calculate the number of vowels in a given string in PHP using different methods. The vowels in English are a, e, i, o, u, and they can be uppercase or lowercase. What is a vowel? Vowels are alphabetic characters that represent a specific pronunciation. There are five vowels in English, including uppercase and lowercase: a, e, i, o, u Example 1 Input: String = "Tutorialspoint" Output: 6 explain The vowels in the string "Tutorialspoint" are u, o, i, a, o, i. There are 6 yuan in total

Static binding (static::) implements late static binding (LSB) in PHP, allowing calling classes to be referenced in static contexts rather than defining classes. 1) The parsing process is performed at runtime, 2) Look up the call class in the inheritance relationship, 3) It may bring performance overhead.

What are the magic methods of PHP? PHP's magic methods include: 1.\_\_construct, used to initialize objects; 2.\_\_destruct, used to clean up resources; 3.\_\_call, handle non-existent method calls; 4.\_\_get, implement dynamic attribute access; 5.\_\_set, implement dynamic attribute settings. These methods are automatically called in certain situations, improving code flexibility and efficiency.
